1. Field of the Invention
The present invention relates to a putter club, and more particularly to a putter club wherein the shock of impact with the golf ball during putting is minimized and which can allow more appropriate putting.
2. Description of the Related Art
Before now, it was generally thought that the flexibility of the shaft of a driver, iron, or putter club has little influence at the time of impact, and that the club head acts independently from the shaft and grip. Consequently, it was a matter of course that attention was given to only the club head and especially to devising the sweet spot, which is the center of gravity.
However, because of the low shock during putting, the flexibility of the shaft is not used in a putter club, as it is in a driver or iron. As a result, it was necessary to consider the "grip-shaft-head" as a single rigid body at the time of impact. Various problems with a conventional putter club 1 are explained on the basis of FIGS. 8 and 9.
FIG. 8 is a side view of the putter club 1 during putting. FIG. 9 is a detail of the putter club 1 during putting. The putter club 1 comprises a shaft 2, a head 3 mounted on one end, the top end of this shaft 2, and a grip 4 mounted on the other end, at the bottom end of the shaft 2. As shown with the dotted lines in FIGS. 8 and 9, when the entire putter club 1 is considered to be a single rigid body as discussed above, the reaction from the golf ball 5 acts as a force causing the putter club 1 (shaft 2) to move around the center of rotation P in a direction opposite to the direction of the putt, at the time of impact during putting.
Consequently, as shown in FIG. 9, a force causes the putter club 1 to rotate in a clockwise direction in the figure around the center of rotation P. This force acts on the hand 7 of the golfer who is holding the grip area 6 and putting. As a result, the golfer putts while this force is acting and the force (or direction, in some cases) imagined by the golfer is somewhat different from the actual force or direction. This makes it difficult to execute correct putting.
In the conventional putter club 1 as shown in FIG. 8, the grip area 6 of the grip 4 is located closer to the grip end 8 than the center of rotation P and the center of rotation P is located on the upper portion of the shaft 2 close to the grip 4. As a result, the counteraction from the golf ball 5, during putting as discussed above, causes the reaction force A of the grip end 8 (shown as a certain size in the figure for purposes of clarity) to become large. The counteraction against the hand 7 of the golfer thereby acts more strongly and easily gives rise to unintentional movement. Furthermore, golfers demand various properties of putter clubs 1, such as gently or firmly striking with the sense of distance imagined by the golfer. Before now, these demands have been difficult to meet on the basis of a correct standard.